Bad Service- Increase premiums

I received an increase email from Vumatel from April. How can this be, this is a fixed contract. This is utter nonsense. I tried calling the office since last week, and still no one called me back. Your current Fibre line speed has been discontinued by Vumatel. To ensure you are not without connectivity, we are moving your product to the closest alternative line speed available. This comes with an increase in upload line speed and a price increase from Vumatel. What is this about?